Health-Enhancing Behaviors

Exercise

Types of Exercise Aerobic Exercise

Elevated heart rate and respiration

Weight training Resistance important for development of lean

muscle mass

Increased activity Increasing daily movement to improve fitness

Benefits of Exercise - Physiological Increases in cardiovascular fitness and

endurance 30-minute/day decreases the risk of chronic disease

Improved circulation Strengthens bones and increases joint flexibility Improves digestion and fat metabolism Increases muscle strength and tone Increased longevity

by age 80, the amount of additional life attributable to aerobic exercise is between 1 and 2 years

Benefits of Exercise - Psychological

Psychological Effects of Exercise Improved mood

Exercise as effective as therapy for depression for most people

Decreased anxiety May decrease stress and protect against effect

of stressors Exercise addiction?

Exercise: Determinants of Regular Exercise

Exercise schedules are usually erratic Lack of time and stress undermine good intentions About 50% of people who initiate a voluntary exercise

program are still doing it after 6 months

Individual Characteristics Gender, weight, social support, self-efficacy predict

exercise adherence

Characteristics of the Setting Convenient and accessible settings predict adherence

Exercise: Characteristics of Interventions Strategies

Stages of Change model helps understand levels of motivation

Cognitive-behavioral strategies promote adherence Telephone and mail reminders are effective in relapse

prevention

Individualized Exercise Programs Understanding motivation and attitudes aids in

development of a program of activities that are liked and are convenient

Diet

Maintaining a Healthy Diet:Overview

Controllable risk for many causes of death 35% of U.S. population gets 5 servings of fruit and

vegetables each day Unhealthy eating contributes to 300,000+ deaths

per year Dietary change is critical for those at risk for

Coronary artery disease, hypertension Diabetes Cancer

Prevalence of Overweight and Obese Americans

Weight Gain/Loss Formula

Wt +/- = cal absorbed through food

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cal spent through metab. & activity

Basal Metabolic Rate and Caloric Intake

Basal Metabolic Rate (BMR) Body’s base rate of energy expenditure Influenced by heredity, age (higher in younger people),

activity level, and body composition (fat tissue has a lower metabolic rate)

Calorie amount of energy needed to raise the temperature of 1 g of

water 1 degree Celsius

Weight Regulation

The Search for Hunger/Satiety Signals Feelings of hunger rise and fall with levels of glucose and insulin Possible link to the number of fat cells in the body

Lateral Hypothalamus (LH) Stimulation leads to hunger Lesioning leads to self-starvation

Ventromedial Hypothalamus (VMH) VMH lesioning leads to hunger VMH stimulation causes an animal to stop eating

Short-Term Appetite Regulation Pancreas hormone insulin helps convert glucose into fat When glucose levels fall, insulin productions increases

and we feel hungry Cholecystokinin (CCK) — satiety hormone produced by

the intestine Ghrelin — appetite stimulant produced by stomach

Long-Term Weight Regulation Laboratory mice with a defective gene for

regulating the hormone leptin become obese

Leptin levels increase with body fat Neurons in the arcuate nucleus (ARC) of

the hypothalamus contain many receptors for leptin

Obesity: Some Basic Facts Measuring Obesity

Body mass index (BMI) — measure of obesity calculated by dividing body weight by the square of a person’s height

Two Weight Extremes

Mortality Rates and BMI Generally speaking, thinner people live longer;

however, very thin people do not have the lowest mortality rates

Weight Control: Why Obesity is a Health Risk

Links with other risk factors, i.e., blood pressure Increases risks during surgery, anesthesia

administration, and childbearing Chief cause of disability

number of people aged 30-49 who cannot care for themselves has jumped by 50%

Problems with health care May not fit in standard wheelchairs X-rays may not penetrate far enough Blood pressure cuffs may not fit

Hazards of Obesity

Male-pattern obesity linked to atherosclerosis, hypertension, diabetes

Complications after surgery Increased risk of several cancers Increased mortality rates from all causes Impact on psychological well-being Metabolic syndrome Weight cycling — repeated weight gains and losses through

repeated dieting

Obesity Theories Set-Point Hypothesis

The point at which an individual’s “weight thermostat” is supposedly set

When the body falls below this weight, an increase in hunger and a lowered metabolic rate may act to restore the lost weight

Positive Incentive Model Food tastes good and is a powerful reinforcer for

eating behavior Social factors and other pleasurable aspects of

eating are part of what is reinforcing.

The Biopsychosocial Model of Obesity - Biology

Heredity Genes thought to contribute approximately 50%

to the likelihood of obesity 60% of obese people had obese biological parents Body weights of adopted children correlate more

strongly with weights of biological parents Body weights of adopted siblings weakly correlated

The Biopsychosocial Model - Psychology

Stress has a direct effect on eating Especially true for adolescents

Greater stress tied to Eating more fatty foods Eating less fruit and vegetables Skipping breakfast More between-meals snacks

Weight Control: Stress and Eating 50% eat more when under stress

Women more likely to eat more under stress Stress removes self-control in dieters/obese Choose foods containing more water, “chewier” Choose salty, low calorie foods Negative emotions – sweet, high-fat foods

50% eat less when under stress Men, compared to women, eat less under stress Non-dieting, non-obese suppress hunger cues

The Biopsychosocial Model - Social

1975: 47% of Americans are overweight or obese 2006: 65% are overweight or obese More prevalent among African-Americans,

Hispanic-Americans, Native Americans Inversely related to socioeconomic status

The Biopsychosocial Model - Social

Cultural variation in ideal body image African-Americans may be less

preoccupied with thinness than European Americans

Acculturation of dietary customs Japanese-American men are 3 times as

likely to be obese as men living in Japan

Weight Control: Factors Associated with Obesity

Particular risk to “apples” rather than “pears” (fat localized in abdomen) More psychologically reactive to stress Greater cardiovascular reactivity

Yo-Yo dieting Loss and regain Affects abdominal fat

Weight Control: Factors Associated with Obesity

Obesity and Dieting as Risk Factors Obesity is a risk factor for obesity High basal insulin levels prompt overeating due

to increased hunger Obese have larger fat cells Cycles of dieting lower metabolic rate

Dieting

Dieting Successful weight loss is often defined as at least a 10% reduction

of initial weight that is maintained for one year 72% of women and 44% of men report having dieted at some point

Why Diets Fail People are not accurate at estimating calorie needs Dieters underestimate consumption People find diets hard to stick with

Diet and Disease Body expends only 3 calories to turn 100 calories of fat

in food into body fat Body expends 25 calories to turn 100 calories of

carbohydrate into body fat Humans have a natural craving for fat (a legacy from our

evolutionary past when food was not plentiful?) Typical Western diet: 40%–45% of total calories are

from fats Poor diet (especially saturated fat) is implicated in one-

third of all cancer deaths in the United States

Weight Control: Treatment of Obesity

Amazon.com has 140,000 titles about dieting Obese individuals attempt to lose weight because

It is considered unattractive (a primary reason) It carries a social stigma (a primary reason) They perceive that it is a health risk It is coupled with psychological distress

Obese - often blamed for their weight Few health practitioners advise losing weight

Maintaining a Healthy Diet:Interventions to Modify Diet Individual interventions

In response to specific health risk Education and self-monitoring are key Cognitive-behavioral interventions

Transtheoretical Model of Change - Different interventions are required for each stage

Precontemplation Contemplation Preparation Action Maintenance

Weight Control: Treatment of Obesity

Dieting Small losses, rarely maintained for long Risk of yo-yo dieting to CHD > than risk of obesity alone Formal investigation of low-carb diets does not suggest they are

more effective than other kinds of diets Fasting – usually employed with other techniques Surgery – stomach stapled to reduce capacity Appetite-Suppressing drugs The multimodal approach

Screening, self-monitoring, control over eating, exercise Controlling self-talk, social support, relapse prevention

Behavioral and Cognitive Therapy Most behavior modification programs include the following components:

Stimulus control Self-control Contingency contracts Social support Careful self-monitoring

Cognitive behavior therapies (CBT) — focus on interdependence of feelings, thoughts, behavior, consequences, social context, and physiology

Weight Control: Evaluation of Cognitive-Behavioral Techniques

Efforts are somewhat successful Losing 2 pounds/ week for 20 weeks Maintenance for 2 years Programs emphasize self-direction, exercise, and

relapse prevention

Health psychologists suggest Sensible eating and exercise Rather than specific weight reduction techniques

Stepped Care for Obesity

Eating Disorders

Eating Disorders: Anorexia Nervosa DSM-IV Criteria

Self-starvation BMI chronically < 18 Intense fear of weight gain Disturbance of body image Amenorrhea for at least three months

Health Hazards of Anorexia Slowed thyroid function Heart arrhythmias Low blood pressure Dry and yellowed skin Anemia Brittle bones

Bulimia Nervosa DSM-IV criteria

At least two bulimic (binge-purge) episodes a week for at least 3 months

Lack of control over eating Behavior designed to avoid weight gain Persistent, exaggerated concern about weight

History and Demographics Strong gender bias: 10 to 1 ratio of women

to men Prevalence

Anorexia nervosa: 0.5% to 1.0% of young adult and adolescent females

Bulimia nervosa: 1.0% to 3.0%

Biological Factors in Eating Disorders

Hypothalamic-pituitary-adrenal Axis (HPA) HPA abnormalities that may promote depression

are linked with both anorexia and bulimia HPA abnormalities return to normal when disordered

eating stops

Heredity and Eating Disorders? Bulimia and identical twins (75% concordance rate) Bulimia and fraternal twins (27% rate) The chances that a young adult woman will

be diagnosed with a clinical eating disorder are much greater if she has a female relative who has anorexia

Family history of major depression, obsessive-compulsive disorder (OCD), and anxiety

Psychological Factors Competitive, semiclosed environments of

some families, athletic teams, and sororities may foster disordered eating

Families of anorexics High achieving Competitive Overprotective Intense interactions Poor conflict resolution

Psychological Factors Families of bulimia patients

Above-average incidence of alcoholism, substance abuse, obesity, and depression

Anorexic and bulimic daughters rate their relationships with their parents as disengaged, unfriendly, and even hostile

Less accepted by their parents, who are perceived as overly critical, neglectful, and poor communicators

Sociocultural View Dieting/disordered eating viewed as

responses to social roles, cultural ideals Shown photographs of ultra-thin actresses

and models, they respond with increased shame, depression, and dissatisfaction with their own bodies

Body Image and the Media Media representation of “ideal” female

weight has decreased to that of the thinnest 5% to 10% of American women

Treatment of Eating Disorders A range of treatments Behavioral treatments have been used,

from force-feeding to family therapy Restoring body weight is the first priority Drug therapy (antidepressants, appetite

suppressants, opiate antagonists) is controversial

Cognitive Behavioral Treatments Exposure-Response Prevention

A behavioral treatment of bulimia nervosa that attempts to prevent purging (and therefore reinforcement) following binge eating

How Effective Are Treatments for Eating Disorders?

Most therapies result in some short-term success, but poor long-term outcome

Cognitive behavior therapy is fairly effective as a primary prevention for binge eating in high-risk women

Some degree of disordered eating may be normative for college women; reduction of disordered eating after graduation is also normative